docs: def get_warmer(self, doc_types=None, indices=None, name=None, querystring_args=None):
          """
          Retrieve warmer
  
          :param doc_types: list of document types
          :param warmer: anything with ``serialize`` method or a dictionary
          :param name: warmer name. If not provided, all warmers will be returned
          :param querystring_args: additional arguments passed as GET params to ES
          """
          name = name or ''
          if not querystring_args:
              querystring_args = {}
          doc_types_str = ''
          if doc_types:
              doc_types_str = '/' + ','.join(doc_types)
          path = '/{0}{1}/_warmer/{2}'.format(','.join(indices), doc_types_str, name)
  
          return self._send_request(method='GET', path=path, params=querystring_args)